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Bridgeport m-head drawbar issues

leeko

Stainless
Joined
Jun 30, 2012
Location
Chicago, USA
Hi all,

I have a couple of issues with the drawbar on my Bridgeport m-head

1) the topmost portion is bent, which causes it to bind in the spindle when the left hand nut is screwed on tight

2) it's too short to reach the threads on my mt2 collets, by about a half-inch or so

I'd like to disassemble it, but I'm having trouble getting the top hex nut off. I understand it's supposed to pull straight off after the set screw is removed, but it's stuck pretty tight. I've tried soaking in evaporust, oil, and a torch, but can't get the thing to budge. There's nothing to pull on with a puller, that I can see, and the gap between the hex portion and the left hand nut is too small anyway. Does anyone have any tips? I'm getting close to just cutting it off, grabbing the LH nut and remaking the drawbar...

I'm not sure why it's too short, either... The threads match on the drawbar and the import collets (3/8-16). Is it possible this drawbar is for B&S#7 collets? Did they also use 3/8-16 threads? Or the other, rarer Bridgeport collets (I forget their designation).

Thanks in advance,

Lee

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This eBay listing has some dimensions and possible clues, like a roll pin? through the hex. Or maybe it is a set screw. Might even be worth buying one.

DRAWBAR for "M" HEAD Bridgeport mill , MILLING MACHINE M1067C NEW! | eBay

You could also ask H&W if they have what you want.

Bridgeport M Head Parts

I have a faint recollection that Hardinge made two different length collets with 2 MT. I will have to look at my collet collection to refresh my memory. Of course, there are 2MT collets with the Bridgeport name on them, so they ought to fit an M head.

Edit: I only found one type of Hardinge 2MT collet, marked 2M and nearly the same length (2.917 on a 1/2 order hole) as the Bridgeport collet (2.977 on a 3/8 order hole). I have a Neal Skokie (Germany) 2MT collet that is noticeably shorter than the Bridgeport.

Looking at the Hardinge collet website, I see that they only have the one kind of 2MT collet (2M). It was the 7 B&S collets that come in two types, 7B (no longer made) and 7 B&S.

Larry
 








 
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